Audio visual system having a serial bus for identifying devices connected to the external terminals of an amplifier in the system

ABSTRACT

In the information processing system, the user can easily grasp the names of terminals that the main information processing device possesses. By transmitting the name data showing each name of multiple terminals  13, 14, 15  that the main information processing device  4  has to the control device  2  via the predetermined communication means  8, 11,  and displaying each name of each terminal that said name data shows on the display means  33  of the control device  2,  the user can easily grasp names of terminals that the main information processing device  4  has.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information processing device,control device and information processing system and methods thereof,and is suitably applied to such as an audio visual (AV) system which isformed by connecting various AV devices to each other.

2. Description of the Related Art

The institute of electrical electronics engineers (IEEE) has beenpromoting to standardize the IEEE 1394 high performance serial bus, thatis known as high speed serial bus (hereinafter referred to as IEEE 1394serial bus) and has proposed to construct the AV system as the householdnetwork by connecting various AV devices existing in the household inutilizing said IEEE 1394 serial bus.

As such AV system, the system is constructed by such as a personalcomputer, a mini disk (MD) player, an audio amplifier, a compact disc(CD) player, and a video tape recorder (VTR) has been developed.

As the external terminal to connect to the other AV device, the audioamplifier is equipped with an external terminal for the IEEE1394 serialbus (hereinafter referred to as IEEE1394 terminal) for connecting the MDplayer to be connected to the personal computer via the IEEE1394 serialbus, an input/output external terminal for the RCA cable fortransmitting/receiving analog audio and video signal between VTRs, andan input external terminal for optical cable for transmitting opticaldigital data to be reproduced from the CD player.

In this case, in the audio amplifier, the identification number toidentify said external terminal is assigned to each external terminal,and also the name “VIDEO” is attached to the input/output externalterminal for the RCA cable, and “CD” is attached to the input externalterminal for optical cable.

Incidentally, in the case where the personal computer obtains theinformation regarding the external terminal of the audio amplifier, itcannot obtain names attached to external terminals such as input/outputexternal terminals for RCA cable and input/output terminals for opticalcable, except the IEEE1394 terminal and can obtain the information onlyon the identification numbers assigned to said external terminals andthe distinction of input/output.

Thus, when the personal computer displays the information on theexternal terminal of the audio amplifier on the display unit, it candisplay names of AV devices connected to said IEEE1394 terminal.However, regarding external terminals other than the IEEE1394, it coulddisplay the information only on identification numbers and thedistinction of input/output of said external terminals. Accordingly, itcould not provide sufficient information on external terminals of theaudio amplifier to the user.

Accordingly, in the case where the user switches the input externalterminal of the audio amplifier by visually confirming the display unitof the personal computer, it caused a problem that the user could notswitch the input external terminal unless he should grasp the name ofsaid input external terminal corresponding to the identification numberof the input external terminal in advance.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of this invention is to provide aninformation processing device, control device and an informationprocessing system and methods thereof, which are capable of easilyidentifying the names of terminals possessed by the informationprocessing device.

The foregoing object and other objects of the invention have beenachieved by the provision of an information processing device, controldevice and an information processing system and methods thereof. Bytransmitting name data showing the names of each of multiple terminalspossessed by the main information processing device to the controldevice via the predetermined communication means, and by displaying thenames of each of terminals that said name data shows on the displaymeans of the control device, the user can easily grasp the name ofterminal possessed by the main information processing device.

The nature, principle and utility of the invention will become moreapparent from the following detailed description when read inconjunction with the accompanying drawings in which like parts aredesignated by like reference numerals or characters.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a block diagram showing the configuration of one embodiment ofthe information processing system according to the present invention;

FIG. 2 is a diagram showing a cycle structure of data transmission;

FIG. 3 is a diagram showing a structure of address space in the CSRarchitecture;

FIG. 4 is a diagram explaining a main CSR offset address, name andoperation;

FIG. 5 is a diagram explaining a general ROM format;

FIG. 6 is a diagram showing bus info block, route directory, and unitdirectory;

FIG. 7 is a diagram explaining the constitution of PCR;

FIGS. 8A to 8D are diagrams explaining the constitutions of oMPR, oPCR,iMPR, and iPCR;

FIG. 9 is a diagram showing the relationship among a plug, plug controlregister, and an isochronous channel;

FIG. 10 is a diagram showing the data structure of the SubunitIdentifier Descriptor;

FIG. 11 is a diagram showing a format of general Subunit IdentifierDescriptor;

FIG. 12 is a diagram showing the values of generation ID;

FIG. 13 is a diagram showing the assignment ranges of the list ID;

FIG. 14 is a diagram showing a stack model for the AV/C command set;

FIG. 15 is a diagram explaining a command and a response in the FCP 85;

FIG. 16 is a diagram explaining a command and a response in the FCP moredetail;

FIG. 17 is a diagram showing the data structure of a packet to betransmitted in an asynchronous transmission mode;

FIGS. 18A to 18C are diagrams showing an example of an AV/C command;

FIGS. 19A and 19B are diagrams showing examples of the AV/C command andthe response;

FIG. 20 is a block diagram showing the construction of a personalcomputer;

FIG. 21 is a block diagram showing the construction of an audioamplifier;

FIG. 22 is a flow chart showing the input external terminal switchingprocessing procedure;

FIG. 23 is a schematic diagram showing the external terminal switchingscreen; and

FIGS. 24A to 24C are schematic diagrams showing the external terminalswitching screen according to the other embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT

Preferred embodiments of this invention will be described with referenceto the accompanying drawings:

In FIG. 1, 1 generally shows the construction of an AV system, and thisAV system comprises a personal computer 2 and a mini disk (MD) player 3,an audio amplifier 4, a compact disc (CD) player 5 and a video taperecorder (VTR) 6.

The personal computer 2 comprises an external terminal for the IEEE1394serial bus (hereinafter referred to as IEEE 1394 terminal) 7 as anexternal terminal and is connected to the MD player 3 via the IEEE 1394serial bus 8 as the communication means to be connected to said IEEE1394 terminal 7.

The MD player 3 comprises IEEE 1394 terminals 9 and 10 as externalterminals, and is connected to the personal computer 2 via the IEEE 1394serial bus 8 to be connected to the IEEE 1394 terminal 9. Andsimultaneously, this MD player 3 is connected to the audio amplifier 4via the IEEE 1394 serial bus 11 as the communication means to beconnected to the IEEE 1394 terminal 10.

The audio amplifier 4 comprises an IEEE 1394 terminal 12 as an externalterminal, an input external terminal for optical cable 13 to transmitoptical digital data defined by the international electrotechnicalCommission (IEC) 60958, an input external terminal for RCA cable 14 totransmit analog audio signal, an input external terminal 15 for RCAcable to transmit analog audio and video signals, and an output externalterminal for RCA cable 16 to transmit analog audio and video signals.

The audio amplifier 4 is connected to the MD player 3 via the IEEE 1394serial bus 11 to be connected to the IEEE 1394 terminal 12, and it isconnected to the CD player 5 via the optical cable 17 as the connectingmeans to be connected to the input external terminal 13, and isconnected to the CD player 5 via the RCA cable 18 as the connectingmeans to be connected to the input external terminal 14, and isconnected to the VTR 6 via the RCA cable 19 as the connecting means tobe connected to the input external terminal 15, and is connected to theVTR 6 via the RCA cable 20 as the connecting means to be connected tothe output external terminal 16.

The CD player 5 comprises an output external terminal for optical cable21 to transmit optical digital data and an output external terminal forRCA cable 22 to transmit analog audio signal as external terminals, andas well as being connected to the audio amplifier 4 via the opticalcable 17 to be connected to the output external terminal 21, this CDplayer 5 is connected to the audio amplifier 4 via the RCA cable 18 tobe connected to the output external terminal 22.

The VTR 6 comprises an output external terminal for RCA cable 23 totransmit analog audio and video signals and an input external terminalfor RCA cable 24 to transmit analog audio and video signals. And as wellas being connected to the audio amplifier 4 via the RCA cable 19 to beconnected to the output external terminal 23, the VTR 6 is connected tothe audio amplifier 4 via the RCA cable 20 to be connected to the inputexternal terminal 24.

At this point, the IEEE 1394 bus interface that connects the personalcomputer 2, the MD player 3 and the audio amplifier 4 each other will bedescribed in the following paragraphs.

FIG. 2 shows the cycle structure of data transmission of the deviceconnected by the IEEE 1394. In the IEEE 1394, data is divided intopackets and transmitted in time division based on the cycle with thelength of 125 μS. This cycle is formed by the cycle start signal to besupplied from the node (either one of devices connected to the bus)having the cycle master operation. Isochronous packet secures the bandrequired for transmission from the head of all cycles (this is called asband even though this is time unit). Accordingly, in the isochronoustransmission, the data transmission within the fixed time is guaranteed.However, if the transmission error occurs, data is lost because there isno protecting system. In the asynchronous transmission in which the nodesecured bus as a result of arbitration transmits asynchronous packetduring the time when each cycle is not used for isochronus transmission,the positive transmission would be guaranteed by using the acknowledgeand retry. However, the transmission timing would not become constant.

In order to conduct the isochronous transmission the predetermined nodemust correspond to the isochronous operation. Moreover, at least one ofnodes that corresponding to the isochronous operation must have thecycle master function. Furthermore, at least one of nodes connected tothe IEEE 1394 series bus 8 to 11 (i.e., personal computer 2, MD player 3and audio amplifier) should have the isochronouse resource managerfunction.

The IEEE 1394 is compliant with the control & status register (CSR)architecture having 64-bit address space defined by the ISO/IEC 13213.FIG. 3 explains the structure of address space of the CSR architecture.The higher level 16 bits are node ID to show the node on each IEEE 1394and the remaining 48 bits are used to specify the address space given toeach node. The higher level 16 bits are further divided into 10-bit ofbus ID and 6-bit of physical ID (node ID of narrow sense). Since thevalue that all bits become 1 is used for specific purpose, 1023 busesand 63 nodes can be specified.

The space to be defined by the higher level 20 bits in the address of256 terabyte to be defined by the lower level 48 bits are divided intothe initial register space, private space and initial memory space to beused for 2048-byte CSR specific register and IEEE 1394 specificregister. The space defined by the lower level 28 bits, if the spacedefined by the upper level 20 bits is the initial register space, theseare used as the configuration read only memory (ROM), the initial unitspace to be used for the node specific usage, and the plug controlregister (PCRs).

FIG. 4 shows main CSR offset addresses, names and functions. The offsetof FIG. 4 shows offset addresses from FFFFF0000000h (the number attachedwith h at the end shows hexadecimal notation) at which initial registerspace starts. The bandwidth available register having the offset 220hshows the bandwidth available to isochronous communications, and onlythe value of node operating as the isochronous resource manager isregarded as effective. More specifically, each node has the CSR of FIG.3, however, regarding the bandwidth available register, only the one forthe isochronous manager is regarded effective. That is, in practice onlythe isochronous resource manager has the bandwidth available register.The maximum value is kept in the bandwidth available register when nobandwidth is allocated to the isochronous communications and the valuedecreases gradually in each time the bandwidth is allocated.

Each bit of the offset 224h to 228h of the channel available registercorresponds respectively to the channel numbers 0 to 63. And when bit is0, this means that the channel has been already allocated. Only channelavailable register of the node operating as the isochronous resourcemanager is effective.

Returning to FIG. 3, configuration ROM based on the general read onlymemory (ROM) format is placed in the address 200h to 400h in the initialregister space. FIG. 5 is a diagram showing the general ROM format. Thenode that is the access unit on the IEEE 1394 and can have multipleunits to operate independently in utilizing the address space commonlyin the node. The unit directories can show the software version andposition to this unit. The positions of bus info block and rootdirectory are fixed, however, positions of other blocks are specified bythe offset address.

FIG. 6 is a diagram showing the bus info block, root directory and theunit directory in detail. In Company ID in the Bus info block, the IDnumber showing the manufacturer of the device, only one ID in the world,is stored. In Chip ID, the ID unique to that device is memorized.Moreover, according to the IEC 61833 standard, in the unit spec ID ofthe unit directory of the device that satisfies the IEC 61883, 00h iswritten in the first octet, Aoh is written in the second octet and 2Dhis written in the third octet. Moreover, 01h is written in the firstoctet of the unit switch version (unit sw version), and 1 is written inthe LSB (Least Significant Bit) of the third octet.

In order to control input/output of the device via the interface thenode has the PCR (Plug Control Register) defined by the IEC 61883 in theaddress 900h to 9FFh in the initial unit space of FIG. 3. And logicallythe concept of plug is materialized in order to form the signal pathsimilar to the analog interface. FIG. 7 is a diagram explaining thestructure of PCR. The PCR has output plug control register (oPCR)showing the output plug and input plug control register (iPCR) showingthe input plug. Moreover, the PCR has output master plug register (oMPR)and input master plug register (iMPR) to show information of output plugor input plug that is unique to each device. Each device never hasmultiple oMPRs and iMPRs respectively. However, it is possible to havemultiple oPCRs and iPCRs corresponding to each plug according to thecapability of the device. The PCR shown in FIG. 7 has 31 oPCRs and iPCRsrespectively. The flow of isochronous data can be controlled byoperating the register corresponding to these plugs.

FIGS. 8A to 8D show diagrams of the structures of oMPR, oPCR, iMPR andiPCR. FIG. 8A shows the structure of oMPR, FIG. 8B shows the structureof oPCR, FIG. 8C shows the structure of iMPR and FIG. 8D shows thestructure of iPCR respectively. In the data rate capability of 2 bits ofthe MSB side of oMPR and iMPR, code showing the maximum transmissionspeed of isochronous data that the device can transmit or receive isstored. The broadcast channel base of oMPR defines the channel numberthat is used for broadcast output.

In the number of output plugs of 5 bits of the LSB side of oMPR, thenumber of output plugs that the device has, that is the value showingthe number of oPCR is stored. In the number of input plugs of 5 bits ofthe LSB side of iMPR, the number of input plugs that the device has,i.e., the value showing the number of iPCR is stored. The non-persistentextension field and the persistent extension field are fields definedfor future extensions.

On-lines of MSB of oPCR and iPCR show the usage condition of plugs. Morespecifically, if its value is 1, this shows that plug is ON-LINE and ifthe value is 0, this shows that plug is OFF-LINE. The value of broadcastconnection counter of oPCR and iPCR shows the existence of broadcastconnection (1) or non-existence of broadcast connection (0). The valuepossessed by the point-to-point connection counter having the width of6-bit of oPCR and iPCR shows the number of point-to-point connectionsthat the plug has.

The value that the channel number having the 6-bit width of oPCR andiPCR has shows the isochronous channel number to which that plug isconnected. The value of data rate having 2-bit width of oPCR shows theactual transmission speed of isochronus data packet to be put out fromthat plug. The code to be stored in the overhead ID having the 4-bitwidth of oPCR shows the over band width of isochronous communications.The value of pay load having the 10-bit width of oPCR shows the maximumvalue of data contained in the isochronous packet that the plug can dealwith.

FIG. 9 is a diagram showing the relation between plug, plug controlregister and isochronous channel. AV devices 71 to 73 are connected bythe IEEE 1394 serial bus. In oPCR[0] to oPCR[2] in which thetransmission speed and the number of oPCRs are regulated by oMPR of theAV device 73, the isochronous data of which channel is designated by theoPCR[1] is transmitted to the channel #1 of the IEEE 1394 serial bus. IniPCR[0] and iPCR[1] in which the transmission speed and the number ofiPCRs are regulated by iMPR of the AV device 71, the AV device 71 readsin the isochronous data transmitted to the channel #1 of the IEEE 1394serial bus. Similarly, the AV device 72 outputs the isochronous data tothe channel #2 designated by the oPCR, and the AV device 71 reads in-the isochronous data from the channel #2 designated by iPCR[1].

With this arrangement, data transmission is conducted between devicesconnected by the IEEE 1394 serial bus. However, in the system of thepresent embodiment, the control and the condition judgment of eachdevice can be conducted in utilizing the AV/C command set regulated asthe command to control devices connected via the IEEE 1394 serial bus.Next, this AV/C command set will be explained.

Firstly, the data construction of the sub-unit identifier descriptor inthe AV/C command set to be used in the system of the present embodimentwill be described referring to FIG. 10˜FIG. 13 in the followingparagraphs. FIG. 10 shows the data construction of the SubunitIdentifier Descriptor. As shown in FIG. 10, data is formed of lists ofhierarchical construction of Subunit Identifier Descriptor. The listshows for example, if it is a tuner, channels that can be received, andif it is a disk, it shows such as musics recorded on that disk. The listof the highest level layer of the hierarchical construction is referredto as route list, and the list 0 becomes the route to the list of thelower level. The route lists exist by the number of objects. Similarly,lists 2 to (n−1) become the route list. At this point, if the AV deviceis a tuner, for example, an object means each channel in the digitalbroadcasting. Moreover, all lists of one hierarchy hold the informationin common.

FIG. 11 shows the format of the General Subunit Identifier Descriptor tobe used in the existing system. The generic information on functions isdescribed in the contents of the descriptor 41. However, the value ofdescriptor length field itself is not included. The generation ID showsthe version of AV/C command set and its value is currently “00h” (hshows hexadecimal notation) as shown in FIG. 12. At this point “00h”means that the data construction and the command are the version 3.0 ofthe AV/C General Specification. Moreover, as shown in FIG. 12, allvalues except “00h” are reserved for the future specifications.

Size of list ID shows the number of bytes of the list ID. Size of objectID shows the number of bytes of the object ID. Size of object positionshows the position (the number of bytes) in the list to be used whenreferring in the case of controlling. Number of root object lists showsthe number of root object lists. Root object list ID shows ID toidentify the root object lists of the highest level of the independenthierarchies respectively.

Subunit dependent length shows the number of bytes of the succeedingsubunit dependent information field. Subunit dependent information isthe field to show unique information to the function. Manufacturerdependent length shows the number of bytes of the succeedingmanufacturer dependent information field. Manufacturer dependentinformation is the field to show the specification information of thevender (maker). In this connection, if the manufacturer dependentinformation does not exist in the descriptor, this field does not exist.

FIG. 13 shows the assignment ranges of the list ID shown in FIG. 11. Asshown in FIG. 13, “0000h to 0FFFh” and “4000h to FFFFh” are reserved asthe assignment ranges for future specifications. “1000h to 3FFFh” and“10000h to max list ID value are prepared to identify the subunit-typedependent information.

Next, the AV/C command set to be used in the system of the presentembodiment will be explained referring to FIG. 14˜FIG. 19. FIG. 14 showsthe stack model of the AV/C command set. As shown in FIG. 14 thephysical layer 81, the link layer 82, the transaction layer 83 and theserial bus management 84 are compliant with the IEEE 1394. The functioncontrol protocol (FCP) 85 is compliant with the IEC 61883. The AV/Ccommand set 86 conforms to the 1394TA spec.

FIG. 15 is a diagram showing the command and response of the FCP85 ofFIG. 16. The FCP is the protocol to control the AV device on the IEEE1394. As shown in FIG. 15, the controlling side is the controller andthe side to be controlled is the target. The transmission or response ofthe command of the FCP is conducted between nodes by using the writetransaction of the asynchronous communication of the IEEE 1394. Thetarget received the data returns an acknowledgement to the controllerfor confirming the receipt of signal.

FIG. 16 is a diagram for explaining further the relation between thecommand and response of the FCP shown in FIG. 15 in detail. The node Ais connected with the node B via the IEEE 1394. The node A is thecontroller and the node B is the target. The command register and theresponse register of 512 bytes each are prepared both in node A and nodeB. As shown in FIG. 16, the controller conveys the command by writingthe command message in the command register 93. Contrary to this, thetarget conveys the answer by writing the response message in theresponse register 92 of the controller. Control information is exchangedonto said two messages. Types of command messages to be transmitted bythe FCP will be described on the CTS in the data field of FIG. 17 to bedescribed later.

FIG. 17 shows the data construction of packet to be transmitted at theasynchronous transmission mode of the AV/C command. The AV/C command setis a command set to control the AV device, and CTS (ID of the commandset)=“0000”. AV/C command frames and response frames are transmittedbetween nodes by using said FCP. In order not to become a burden to thebus and the AV device, the response to the command is to be conductedwithin 100 ms. As shown in FIG. 17, the data of asynchronous packets isformed in 32 bits horizontal direction (=1 quadlet). The upper stage inFig. shows the packet header part and the lower stage shows the datablock. The destination-ID shows the addressee.

CTS shows ID of the command set. In the AV/C command set, CTS=“0000”.The ctype/response field shows the function classification of thecommand when the packet is command. And when the packet is response, itshows the processing result of the command. The command is roughlyclassified into four(4) types: i.e., (1) the command to control thefunction from outside (CONTROL), (2) the command to inquire thecondition from outside (STATUS), (3) the command to inquire theexistence or non-existence of support of the control command fromoutside (GENERAL INQUIRY (existence or non-existence of support ofopcode) and SPECIFIC INQUIRY (existence or non-existence of support ofopcode and operands)), and (4) the command to request to notify thechange of condition (NOTIFY).

The response is returned according to the command type. Regarding theresponse to the CONTROL command, there are NOT IMPLEMENTED, ACCEPTED,REJECTED and INTERIM. Regarding the response to the STATUS command,there are NOT IMPLEMENTED, REJECTED, IN TRANSITION and STABLE. Regardingthe response to the GENERAL INQUIRY and SPECIFIC INQUIRY commands, thereare IMPLEMENTED and NOT IMPLEMENTED. Regarding the response to theNOTIFY command, there are NOT IMPLEMENTED, REJECTED, INTERIM andCHANGED.

Subunit type is provided to specify the function in the device, such asthe tape recorder/player and tuner is assigned. In order to identifywhen multiple subunits of the same type exist, addressing is conductedby the subunit ID as the ID number. Opcode shows the command and operandshows the parameter of the command. Additional operands are fields to beadded if necessary. Also, padding is the field to be added as occasiondemands. Data cyclic redundancy check (CRC) is used for the error checkwhen transmitting data.

FIGS. 18A to 18C show detailed examples of the AV/C command. FIG. 18Ashows a detailed example of ctype/response. The upper stage in Figureshows Command, and the lower stage in Figure shows Response. CONTROL isassigned to “0000”, STATUS is assigned to “0001”, SPECIFIC INQUIRY to“0010”, NOTIFY to “0011”, and GENERAL INQUIRY is assigned to “0100”.“0101 to 0111” are reserved for future specification. Moreover, NOTIMPLEMENTED is assigned to “1000”, ACCEPTED to “1001”, REJECTED to“1010”, IN TRANSITION to “1011”, IMPLEMENTED/STABLE to “1100”, CHANGEDto “1101”, and INTERIM is assigned to “1111”. “1110” is reserved for thefuture specification.

FIG. 18B shows a detailed example of SUBUNIT TYPE. Video Monitor isassigned to “00000”, Disk Recorder/Player is assigned to “00011”, TapeRecorder/Player is assigned to “00100”, Tuner is to “00101”, VideoCamera is to “00111”, Vendor Unique is to “11100”, Subunit type extendedto next byte is assigned to “11110”. Incidentally, Unit is assigned to“11111”, however, it is used when sending to the device and such asON/OFF of the power source can be listed.

FIG. 18C shows a detailed example of Opcode. Opcode table exists in eachsubunit type, and here it shows the opcode at the time when the subunittype is Tape recorder/player. Moreover, operand is defined per theopcode. Here, VENDOR-DEPENDENT is assigned to “00h”, SEARCH MODE to“50h”, TIMECODE to “51h”, ATN to “52h”, OPEN MIC to “60h”, READ MIC to“61h”, WRITE MIC to “62h”, LOAD MEDIUM is assigned to “C1h”, RECORD isassigned to “C2h”, PLLAY is assigned to “C3h” and WIND is assigned to“C4h”.

FIGS. 19A and 19B show detailed examples of the AV/C command andresponse. In the case of conducting the play instruction to thereproduction device as the target (consumer), the controller sends outthe command as shown in FIG. 19A. Since this command uses the AV/Ccommand set, CTS=“0000”. Because the command (CONTROL) to control thedevice from outside is used in ctype, ctype=“0000” (refer to FIG. 18A).Since subunit type is Tape Recorder/Player, subunit type=“00100” (referto FIG. 18B). Id shows when ID0, and id=000. Opcode becomes “C3h” thatmeans PLAY (refer to FIG. 18C). Operand becomes “75h” meaning FORWARD.And when it is reproduced, the target returns the response as shown inFIG. 19B to the controller. At this point, Accepted is entered intoResponse, response=“1001” (refer to 18A). All others except Response arethe same as FIG. 19A, the explanation will be omitted.

Next, the construction of the personal computer 2 is shown in FIG. 20.The central processing unit (CPU) 30 is a circuit to control thepersonal computer 2 as a whole. When the user operation information isentered from an input unit 31 having the keyboard and the mouse, the CPUreads out the software program from a hard disc drive (HDD) 32 based onsaid operation information, and controls the function of each circuit byexecuting the software program read out.

More specifically, the CPU 30 forms display screen data based on theoperation information of the user, and sending this out to the displayunit 33, it displays the data on said display unit 33. Moreover, the CPU30 forms control data to control the switching operation of externalterminals in the audio amplifier 4 based on the operation information ofthe user, and transmits this to the audio amplifier 4 through the IEEE1394 interface 34, the IEEE 1394 serial bus 8, the MD player 3 and theIEEE 1394 serial bus 11 successively. On the other hand, when theresponse data to said control data is supplied from the audio amplifier4 successively through the IEEE 1394 serial bus 11, MD player 3, IEEE1394 serial bus 8 and the IEEE 1394 interface 14, the CPU 30 controlsthe function of each circuit based on said response data supplied. Inthis connection, the AV/C command set is used to transmit said controldata and the response data for example.

More specifically, as shown in FIG. 21, the audio amplifier 4 notifiesthe control data to be supplied via the MD player 3 from the personalcomputer 2 to the CPU 42. And said CPU 42 controls the function of eachcircuit unit based on this control data.

In the audio amplifier 4, the unique identification numbers are assignedto the IEEE 1394 terminal 12 and each input external terminals 13 to 15.And “CD DIGITAL” is assigned to the input external terminal 13 foroptical cable, “CD” is assigned to the input external terminal 14 forRCA cable to transmit analog audio signal, and the name of “VIDEO” isattached to the input external terminal 15 for RCA cable to input analogaudio and video signals, and the name data related to the names of inputexternal terminals 13 to 15 except the IEEE 1394 terminal are memorizedin the memory unit 43 in advance. Moreover, these name data may bememorized on the memory space shown in FIG. 3. Or these may be memorizedin the list of hierarchical construction as described in the subunitidentifier descriptor of FIG. 10.

The CPU 42 reads out the name data from the memory unit 43 in responseto the-request from the personal computer 2 and transmits said name dataread out to the personal computer 2 via the IEEE 1394 interface 41 andthe MD player 3.

Then, the CPU 42 forms an input switching signal responding to therequest from the personal computer 2 and transmitting said inputswitching signal, selects the desired input external terminal from amongthe IEEE 1394 terminal 12 and input external terminals 13 to 15 andswitches the input, and transmits the input data to be entered from saidselected input external terminal to the amplifier 45.

The amplifier 45 forms an output data by applying the equalizerprocessing to amplify the signal level of the predetermined band to theinput data to be supplied from the input switching unit 44, andoutputting this to the MD player 3 via the IEEE 1394 interface 41 andthe IEEE 1394 terminal 12, outputs this to the VTR 6 via the outputexternal terminal 45.

At this point, the input external terminal switching processingprocedure for switching the input external terminal of the audioamplifier 4 will be explained. In FIG. 22, when the CPU 30 of thepersonal computer 2 judges that the user has started the operation toswitch the input of the audio amplifier 4 via the input 31 at the stepSP2 entered from the step SP1, moves to the following step SP3 and formsthe name request data for requesting to transmit names of input externalterminals 13 to 15 possessed by the audio amplifier 4 to said personalcomputer 2 and outputs this to the audio amplifier.

Then, at the step SP5, entering from the step SP4, when the CPU 42 ofthe audio amplifier 4 receives the name request data transmitted fromthe personal computer 2 via the MD player 3, moves to the following stepSP6. Then, operating the name data as the transmission means, the CPU 42reads out the name data memorized in the memory unit 43 and transmitsthis to the personal computer 2 via the MD player 3.

At the step SP7, when the CPU 30 of the personal computer 2 obtains thename of the IEEE 1394 terminal 12 via the IEEE 1394 serial bus 8 and 11(after receiving the name data transmitted from the audio amplifier 4via the MD player 3), moves to the step SP8. And as shown in FIG. 23 itfunctions as the display control means and displays the name list ofinput external terminal that the audio amplifier 4 has on the displayunit 33 as the output terminal switching screen 50.

At the step SP9, the CPU 30 functions as the selection means, and whenit judges that the user selects the desired terminal from input externalterminals displayed on the external terminal switching screen such as bymoving the mouse cursor, moves to the following step SP10 and functionsas the selected terminal identification number data transmission means.And the CPU 30 forms the switching request data for switching the inputto the input external terminal having the name selected (i.e., selectedterminal identification number data), and transmits this to the audioamplifier 4 via the MD player 3.

At the step SP11, the CPU 42 of the audio amplifier 4 functions as theselected terminal identification number data receiving means. And whenthe CPU 42 receives the switching request data transmitted from thepersonal computer 2 via the MD player 3, it moves to the following stepSP12 and forms the switching request accept data showing the receipt ofsaid switching request data and transmits this to the personal computer2 via the MD player 3.

At the step SP13, the CPU 42 of the audio amplifier 4 functions as theswitching control means. And the CPU 42 forms an input switching signalbased on the switching request data transmitted from the personalcomputer 2, and by transmitting this to the input switching unit 44, theCPU 42 of the audio amplifier 4 terminates said processing procedure atthe step SP14.

On the other hand, at the step SP15, the CPU 30 of the personal computer2, after receiving the switching request accept data transmitted fromthe audio amplifier 4 via the MD player 3, moves to the step SP16 andterminates said processing procedure.

Thus, in the AV system 1, when transmitting and recording the audio dataMD formed of optical digital data to be reproduced from the CD player 5,the recording operation is executed by selecting “CD DIGITAL” from amonginput external terminals displayed on the display screen 50 in FIG. 23and by switching the input of the audio amplifier 4.

According to the foregoing construction, the audio amplifier 4 possessesthe IEEE 1394 terminal 12 and input external terminals 13 to 15excluding said IEEE 1394 terminal 12 as the input external terminals,and the name data showing the names of input external terminals 13 to 15except said IEEE 1394 terminal 12 are memorized in the memory unit 43 inadvance.

Under this condition, the CPU 42 of the audio amplifier 4, informing thename data memorized in the memory unit 43 to the personal computer 2responding to the request of the personal computer 2, displays the namesof input external terminals 12 to 15 possessed by said audio amplifieron the display unit 33 of the personal computer 2.

Thus, the user can easily grasp input external terminals of the audioamplifier 4 just by observing the list of input external terminalsdisplayed on the display unit 33 of the personal computer 2. And thus,the user, by selecting the desired input external terminal from the listof said input external terminals, can switch the input of the audioamplifier 4 easily.

According to the foregoing construction, by informing the names of inputexternal terminals 13 to 15 possessed by the audio amplifier 4 to thepersonal computer 2 and displaying the names of the IEEE 1394 terminal12 and input external terminals 13 to 15 excluding said IEEE 1394terminal 12 on the display unit 33, the user can easily grasp the inputexternal terminals of the audio amplifier 4. And thus, the user canconduct the input switching of said audio amplifier 4 easily.

The embodiment described above has dealt with the case of memorizing thenames attached to input external terminals 13 to 15 respectively in thememory unit 43 as the name data. However, the present invention is notonly limited to this but also the name of input external terminal may bechanged to the name of AV device connected to sad input externalterminal such as “VHS”, “8 mm”, and memorized in the memory unit 43 bythe user operating the input unit 31 and the audio amplifier 4 of thepersonal computer 2. In this case, when the user visually confirms thelist of names of input external terminals displayed on the display unit33 of the personal computer 2, he can recognize the input externalterminals of audio amplifier 4 more easily. And furthermore, he caneasily recognize the AV devices connected to said input externalterminals.

Furthermore, the embodiment described above has dealt with the case ofdisplaying the list of input external terminals that the audio amplifier4 has on the display unit 33 of the personal computer 2 as the externalterminal switching screen 50 as shown in FIG. 23. However, the presentinvention is not only limited to this but also by displaying at leastone of names of input external terminals 13 to 15 other than the IEEE1394 terminal 12, and the user operating the input unit 31 of thepersonal computer 2, the display of names of input external terminals 13to 15 may be switched successively. In this case, as the method toselect the input external terminal, there is the method to select theinput external terminal displayed on the display unit 33 when the userpresses an input external terminal switching button provided in theinput unit 31, or there is the method to select the input externalterminal displayed for the fixed time. FIGS. 24A to 24C are displayexamples when one name out of input external terminals 13 to 15 issuccessively shifted and displayed on the display unit 33.

Furthermore, the embodiment described above has dealt with the case ofshifting the input external terminals 12˜15 of the audio amplifier 4 bythe personal computer 2. However, the present invention is not onlylimited to this but also the output external terminals of the audioamplifier 4 may be shifted.

Furthermore, the embodiment described above has dealt with the case ofconstructing the AV system 1 adopting the personal computer 2 as thecontrol device, adopting the audio amplifier 4 as the main informationprocessing device, and adopting the MD player 3, CD player 5 and the VTR6 as the sub information processing devices. However, the presentinvention is -not only limited to this but also the informationprocessing system may be constructed by various other control device,main information processing device and multiple sub informationprocessing devices.

According to the present invention as described above, by transmittingthe name data showing the names of multiple terminals possessed by themain information processing device to the control device via thepredetermined communication means, and displaying: the name of eachterminal that said name data shows on the display means of the controldevice, the user can easily grasp the names of terminals that the maininformation processing device has.

While there has been described in connection with the preferredembodiments of the invention, it is obvious to those skilled in the artthat various changes and modifications may be aimed, therefore, to coverin the appended claims all such changes and modifications as fall withinthe true spirit and scope of the invention.

1-16. (canceled)
 17. An information processing system comprised of amain information processing device controlled by a control devicethrough a communication means, and sub-information processing devicesconnected to said main information processing device, said communicationmeans being a serial bus, said main information processing device beingan amplifier, and said control device being a computer; wherein: saidmain information processing device comprises: a plurality of terminalsfor connecting to a plurality of sub-information processing devices witha corresponding plurality of connecting means; at least one of saidconnecting means being said communication means; memory means formemorizing name data indicating names of said terminals; wherein saidmemory means changes the name data indicating the names of saidterminals in accordance with a user's input operation, wherein the namedata includes unique manufacturer and chip numbers; and name datatransmission means for transmitting said name data to said controldevice through the communication means; and said control devicecomprises: name data receiving means for receiving said name data whichis transmitted from said main information processing device through saidcommunication means; and display control means for displaying the namesof said terminals on the display means based on said name data.